LONG POST: Those with dual batteries....Need input on problem with my system

[matoolie]

I have a dual battery system using the Westin T-max controller system. You can find some info. From link in my signature. Well, I ran into a problem with the system this morning and I think I know how to fix but want to put it out here for others to comment and maybe consider how their system works.

I opened the garage door this morning to remote start the 4Runner. No dice. No flashing vehicle lights when I pushed button on transmitter. Right then pretty sure main vehicle battery was dead. Went outside and sure enough completely dead. No door locks. No dome light. Nothing. I looked at t-max controller and it said aux battery voltage OK but main battery did not register, which means below 11vdc. I pushed the button on the controller to link the two batteries together to start and make vehicle functional and no change. Nothing.

After troubleshooting and evaluating here was my situation:
1. Main battery had a bad cell and was at 6vdc.
2. I could not connect the good aux battery at 13+vdc with controller to start vehicle.
3. The controller is powered by the main battery only. I found this out when I removed the main battery for replacement and the controller was completely dead.
4. My assumption based on above........the controller and/or solenoid require minimum voltage above 6vdc on main battery to function.
5. I checked the install instructions and it states supply voltage is 8-16vdc.
6. The wiring diagram in the instructions shows the solenoid uses the main battery + voltage only (labeled as jump wire in diagram) to activate. The controller provides ground through green wire to close solenoid and link batteries.
7. Based on above, it seems the system is nonfunctional below 8vdc on the main battery as designed. I emailed Westin with this question and waiting on verification.

I like the idea I can normally push a button on the controller to connect aux. battery when main is "dead" to start. Say below 11vdc, but above 8vdc. BUT......I am pissed the system as designed does not function when a cell goes bad in main battery and thus leaving vehicle dead. Unacceptable!!

My proposed solution is to place a manual switch on the "jump wire" that provides positive voltage to close the solenoid and allow me to choose either the main battery or aux. battery voltage to close the solenoid and allow a good aux. battery to start the vehicle in the situation I encountered with the main.

HOWEVER........not to sure about after the vehicle is started. Now I would have the bad main battery at say 6vdc and good aux battery at 12vdc linked together in parallel being both connected to the alternator. I could physically disconnect the main temporarily and thus making the aux. my main and eliminating the bad original main from the picture. Or remove the battery link (with controller or added manual switch) and have only the main battery at 6vdc and the alternator power the vehicle. Or......use an all new better system without this problem? Lol!

Hmmmm... what are thoughts? Is this an issue with other dual battery systems with controller. If not, how is it resolved? I know some use the ultimate KISS principle and use a big ole manual battery switch used in boats for switching batteries and non issue.

 

[nevada]

I have a dual battery system using the Westin T-max controller system. You can find some info. From link in my signature. Well, I ran into a problem with the system this morning and I think I know how to fix but want to put it out here for others to comment and maybe consider how their system works.

I opened the garage door this morning to remote start the 4Runner. No dice. No flashing vehicle lights when I pushed button on transmitter. Right then pretty sure main vehicle battery was dead. Went outside and sure enough completely dead. No door locks. No dome light. Nothing. I looked at t-max controller and it said aux battery voltage OK but main battery did not register, which means below 11vdc. I pushed the button on the controller to link the two batteries together to start and make vehicle functional and no change. Nothing.

After troubleshooting and evaluating here was my situation:
1. Main battery had a bad cell and was at 6vdc.
2. I could not connect the good aux battery at 13+vdc with controller to start vehicle.
3. The controller is powered by the main battery only. I found this out when I removed the main battery for replacement and the controller was completely dead.
4. My assumption based on above........the controller and/or solenoid require minimum voltage above 6vdc on main battery to function.
5. I checked the install instructions and it states supply voltage is 8-16vdc.
6. The wiring diagram in the instructions shows the solenoid uses the main battery + voltage only (labeled as jump wire in diagram) to activate. The controller provides ground through green wire to close solenoid and link batteries.
7. Based on above, it seems the system is nonfunctional below 8vdc on the main battery as designed. I emailed Westin with this question and waiting on verification.

I like the idea I can normally push a button on the controller to connect aux. battery when main is "dead" to start. Say below 11vdc, but above 8vdc. BUT......I am pissed the system as designed does not function when a cell goes bad in main battery and thus leaving vehicle dead. Unacceptable!!

My proposed solution is to place a manual switch on the "jump wire" that provides positive voltage to close the solenoid and allow me to choose either the main battery or aux. battery voltage to close the solenoid and allow a good aux. battery to start the vehicle in the situation I encountered with the main.

HOWEVER........not to sure about after the vehicle is started. Now I would have the bad main battery at say 6vdc and good aux battery at 12vdc linked together in parallel being both connected to the alternator. I could physically disconnect the main temporarily and thus making the aux. my main and eliminating the bad original main from the picture. Or remove the battery link (with controller or added manual switch) and have only the main battery at 6vdc and the alternator power the vehicle. Or......use an all new better system without this problem? Lol!

Hmmmm... what are thoughts? Is this an issue with other dual battery systems with controller. If not, how is it resolved? I know some use the ultimate KISS principle and use a big ole manual battery switch used in boats for switching batteries and non issue.

I use the manual system.
however, I have ran into the issue you had. where the main battery went flat, but that was also where the signal came from to activate my switch to connect the 2. so even though my 2nd battery was full charged, I couldn't access it.

I just changed the power source to the second battery. I cant remember now, I may have power coming from both, just in case.

I have used it this way several times now, because of mistakes on my part. leaving a light/fan or some other accessory on, and thus killing the battery. a simple flip of the switch gets me going again.

typically, after this happens, I connect a battery charger to the main battery, and bring it back to life. never rely on the vehicle to do it.